1. Technical Field
The invention relates generally to the field of hydrocarbon wellbore systems. More specifically, the invention relates to the analysis and/or control of drilling operations based on downhole parameters.
2. Related Art
The harvesting of hydrocarbons from a subterranean formation involves the deployment of a drilling tool into the earth. The drilling tool is driven into the earth from a drilling rig to create a wellbore through which hydrocarbons are produced. During the drilling process, it is desirable to collect information about the drilling operation and the underground formations. Sensors are provided in various portions of the surface and/or downhole systems to generate data about the wellbore, the earth formations, and the operating conditions, among others. The data is collected and analyzed so that decisions may be made concerning the drilling operation and the earth formations.
Typically, a drilling operator is present at the drilling rig to collect and consider data about the wellsite. Drilling operators monitor the data to see if any problems exist, and to make the necessary adjustments to the mechanical or electrical systems of the drilling rig. For example, the drilling operator may adjust the drilling speed, the drilling direction, the wellbore pressures and other conditions. By making adjustments, the drilling operator may control the drilling operation to generate the desired results. The drilling operator often relies on his general understanding or experience to operate the drilling equipment so that the wellbore is drilled in the most efficient manner to achieve the desired wellbore path, preferably at the lowest possible cost.
The driller will typically directly exercise control of the wellbore operation from a surface control station. By manipulating the data, the wellbore operator can often prevent damage to the drilling tool or the wellbore which could destroy or hinder the wellbore operation. Additionally, the information may be used to determine a desired drilling path, optimum conditions or otherwise benefit the drilling process.
Various techniques have been developed to assist in the control of drilling operations at the wellsite. One such technique involves the use of surface control systems to control the downhole drilling tools. Examples of surface drilling control system are described in U.S. Pat. No. 6,662,110, assigned to the assignee of the present invention. In such cases, control of the drilling operation of the wellsite occurs at the wellsite. Typically, one or more experienced drilling operators is positioned at the wellsite to monitor and control the drilling operation.
In many cases, the drilling tool is capable of collecting downhole data during the drilling operation. Such cases may include, for example, logging while drilling or measurement while drilling. Additionally, the drilling tool may be removed from the wellbore to send formation evaluation tools downhole for further investigation. These formation evaluation tools are used to test and/or sample fluid in the wellbore and/or the surrounding formation. Examples of such formation evaluation tools may include, for example, wireline testing and sampling tools, such as those described in U.S. Pat. Nos. 4,860,581 and 4,936,439, assigned to the assignee of the present invention.
The information gathered by the formation evaluation tool is typically sent to the surface (either by wireline or by retrieval of the tool). Formation evaluation information is often used, for example, to determine where produceable resources are located. Once the formation evaluation tool has completed its investigation, it is removed and the drilling tool may be reinserted to continue the drilling process.
Despite these advances in drilling operations, there remains a need to control the drilling operations of one or more wellsites from an offsite location. It is desirable that such a system be capable of incorporating a variety of data from one or more wellsites, and convey commands in response thereto, preferably in real time. It is further desirable that such a system be capable of automatic and/or manual actuation of such commands from the offsite location to reduce or eliminate the need for drilling operators at the wellsite and/or increase the level of expertise available to the wellsite(s).